1. Field of the Invention
The present invention relates generally to a rotatable dual head inflation device, and in particular to a rotatable dual head inflation device which can be used with a French style tire valve and an American style tire valve.
2. The Prior Arts
FIGS. 1A and 1B are cross sectional views showing two conventional rotatable inflation devices 7, 8 which are invented by the applicants, and are designed to cooperate with a French style tire valve and an American style tire valve. The inflation devices shown in FIGS. 1A and 1B are to replace the clamp-style with the rotatable style when connected with the French style tire valve and the American style tire valve. By the rotatable and threaded connection, the two styles of the valve mouths can be securely connected with the inflation devices. The rotatable and threaded connection ensures that the inflation device is firmly connected to the tire valve while the clamp-style inflation device only uses a rubber washer to clamp the outside of the tire valve. The clamp style connection lacks axial force so that the huge pressure during inflation action may separate the inflation device from the tire valve. Therefore, the rotatable style inflation device is more suitable for the high pressure inflation device such as Carbon-dioxide inflation device.
FIG. 1A shows the conventional rotatable inflation device 7 suitable for the French style tire valve F and FIG. 1B shows the conventional rotatable inflation device 8 suitable for the American style tire valve U. Each of the inflation devices includes a central tube 60 which includes a reception chamber 61 at one end and a valve mouth 72/82 is received in the reception chamber 61. The difference between the valve mouths 72 and 82 is that the valve mouth 72 is to be connected with the French style tire valve F and seals at the shoulder portion of the French style tire valve F, and an inlet end of the French style tire valve F can insert into the valve mouth 72. A core tube 83 is received in the central hole of the valve mouth 82 and the outer contour of the core tube 83 is corresponding to the central hole of the valve mouth 82. The core tube 83 has multiple passages 832. A core piece 831 is formed at the center of the passages 832 so as to push the rod of the American style tire valve U to introduce the pressurized air into the tire. In addition to the reception chamber 61, the central tube 60 includes a guide tube 62 at an end opposite to the reception chamber 61. Referring to FIGS. 2A and 2B, the guide tube 62 of the central tube 60 has two different connection forms. FIG. 2A shows a threaded rod 63 is connected to the guide tube 62 and the threaded rod 63 is connected to the head 51 of the tire pump 50. The head 51 is connected with the body 52 and includes a passage 511 which includes an outlet end 512 having inner threads so as to be connected with the threaded rod 63. A recess is defined in the opening of the outlet end 512 and an O-ring 513 is engaged with the recess so as to form a sealing feature when the threaded rod 63 is connected to the outlet end 512. Referring to FIG. 2B, the other form of the guide tube 62 includes a connection end 64 which is connected with a hose 53 of the tire pump (not shown). An end mount 531 is mounted to hold the hose 53 and the connection end 64 so as to reinforce the connection.
Referring to FIGS. 1A and 1B, the central tube 60 of the inflation device 7/8 is received in a casing 70/80. The casing 70/80 includes an inner space 701/801 enclosing the wall of the reception chamber 61. A first threaded portion 702/802 is defined in an open end of the casing 70/80 and the other end of the casing 70/80 includes a connection end 703/803 which has a second threaded portion 704/804 at the axial direction of the inflation devices 7/8. The difference between the second threaded portions 704 and 804 is that the diameter of the second threaded portion 704 is corresponding to the threaded portion of the French style tire valve F and the second threaded portion 804 is corresponding to the threaded portion of the American style tire valve U, such that the second threaded portions 704 and 804 can be threadedly connected with the French style tire valve and the American style tire valve, respectively. A ring-shaped end cap 71/81 is sleeved on the outside of the guide tube 62 and is provided with an opening 711/811 defined centrally therethrough such that the guide tube 62 is engaged with the opening 711/811. The end cap 71/81 includes a third threaded portion 712/812 which is threadedly connected with the first threaded portion 702/802 to connect the end cap 71/81 to the casing 70/80, and mounted to the outside of the reception chamber 61.
The characteristic of the inflation device 7 for the French style tire valve F and the inflation device 8 for the American style tire valve U is that the reception chamber 61 couples with the casing 70/80. The user only needs to change the casing 70/80 and the valve mouth 72/82 on the tire pump 50, then the tire pump 50 can be connected with the French style tire valve F and the American style tire valve U. It can reduce the manufacturing cost and is easy to change the parts. Moreover, the inflation device 7/8 is threadedly connected to the tire valves, which overcomes the disadvantage of the conventional clamp-type inflation device. However, the inflation devices 7 and 8 can not be cooperated with the tire pump 50 and the hose 53 simultaneously. Therefore, the inflation devices 7 and 8 are two independent units. The user has to keep the tire pump 50 and the two inflation devices 7 and 8 at hand. It is inconvenient.